Detonating fuze system

ABSTRACT

A MILD DETONATING FUZE SYSTEM HAVING AN ASSURED CONTINUITY OF SHOCKWAVE PROPAGATION. THE CORE PORTION OF A STRIPPED END OF A MILD DETONATING CORD, PROTRUDING FROM THE END OF A FERRULE, IS EMBEDDED IN A HIGH EXPLOSIVE FILLER WITHIN A BOOSTER SHELL CUP THAT IS SECURED TO THE FERRULE.

Patented Mar. 23, 1971 3,572,246 DETONATING FUZE SYSTEM George F. Hare,Feasterville, and Bruce W. Travor, Holland, Pa., assignors to the UnitedStates of America as represented by the Secretary of the Army Filed Oct.23, 1968, Ser. No. 770,029

Int. Cl. F4211 3/10 U.S. Cl. 1102-27 2 Claims ABSTRACT OF THE DISCLOSUREA mild detonating fuze system having an assured continuity of shockwavepropagation. The core portion of a stripped end of a mild detonatingcord, protruding from the end of a ferrule, is embedded in a highexplosive ller within a booster shell cup that is secured to theferrule.

The invention described herein may be manufactured, used, and licensedby or for the Government for governmental purposes without the paymentto us of any royalty thereon.

This invention relates to a mild detonating fuze system and, moreparticularly, to one having a booster end transfer arrangement.

In mild detonating fuze systems, lhereinafter referred to as MDP`systems, a problem has existed in the discontinuity of shockwavepropagation caused by air gaps adjacent a booster end transferarrangement. When an air gap is present the shockwave decays rapidly inthe propagation train, which results in no propagation or a lower ordershockwave which decays entirely within a few inches of travel in the MDFcore. An old method for solving this problem was to increase thegrains/foot of the basic Pentaerythrite Tetranitrate, hereinafterreferred to as PETN, core. This method was unsatisfactory since itincreased the weight of the MDF system and caused problems of retainingthe core in the r,fittings due to the greater shock force.

One of the objects of the invention 'therefor is to provide a detonatingfuze system in which the .foregoing disadvantage is eliminated.

Another object of the invention is to provide such a system which hasmaximum reliability and is minimally light in hardware weight.

These and other objects, advantages and features will become moreapparent from the following description and accompanying drawing whichis a longitudinal sectional view of a detonating fuze system embodyingthe principles of the invention.

In actual use of the invention, both ends of the explosive core of adetonating cord are directly embedded in a high explosive contained inthe respective booster and transfer assembly at each end of the cord,and thus while the drawing shows only one end of a detonating cord, itis understood that a duplicate arrangement exists at the othersymmetrical end of the cord.

The mild detonating cord is a multi-braided type having a lead sheathedexplosive core 12 surrounded by multiple layers of suitable materialssuch as polyethylene, fiber glass and polytetratiuoroethylene, commonlyknown as Teon, which protect the core from breaking while permittingflexibility in the cord. Each end of cord 10 is stripped in successivestages thereby exposing layers 14, 16, 18 and the end portion 20 of core12. A centrally apertured ferrule 22 is itted over the end of cord 10and secured thereto by suitable epoxy. Ferrule 22 has at its forward enda protruding head portion 24 and an external annular groove 26 forpurposes hereinafter described. Core end portion 20 protrudes from theforward end of ferrule 22 and is embedded in a high explosive ller 28such as PETN which is contained within cup 30 of the respective boosterand transfer assembly 32. Cup 30 also has contained therein an annularring 34 having at its forward end a conical inner surface 36 taperinginwardly and at its rearward end an annular ange 38 which forms acentral recess 40 at said rearward end. Booster and transfer assembly 32is connected to ferrule 22 by sliding cup 30l over the forward end offerrule 22, with core end portion 20 extending through ring 34 and intoller 28, until head portion 24 of ferrule 22 seats in recess 40 of ring34. Cup 30 is secured to the forward end of ferrule 22 by suitable epoxyand by crimping the end of cup 30 into groove 26 as at 42. A retainingsleeve 44, preferably of a lightweight metal such as aluminum, isIsecured to cord 10 by suitably epoxy material and serves to holdassembly 32 to ferrule 22 and also to protect the stripped end of cord16 from being broken or otherwise damaged. The forward end portion ofsleeve 44 has annular internal flange 46, which, when sleeve 44 isfitted over cord 10, holds cup 30 securely against ferrule 22. When cup30` is properly positioned with respect to ferrule 22 as shown in thedrawing, the conical inner surface 36 provides a space around the coreend portion 20 projecting beyond the body of ring 34 and into tiller 28.This space also contains the high explosive iller 28 so that with theend of the explosive being surrounded by high explosive iller, there isno air gap present between the explosive core and the explosive fillersufficient to prevent propagation of high order detonation of the dillerso that reliable continuity of shockwave propagation is obtained.

Various modioations, changes or alterations may be resorted to withoutdeparting from the scope of the invention as defined in the appendedclaims.

We claim:

1. A mild detonating fuze system including:

a mild detonating cord containing an explosive core,

an end of said cord being stripped to expose a portion of said core,

a centrally apertured ferrule secured to said cord with a portion ofsaid core portion protruding from said ferrule, and

a booster end transfer arrangement secured to said ferrule,

said booster end transfer arrangement comprising a booster shell cup anda high explosive `filler in said cup, said iiller having a rearwardlyprotruding conical portion thereof surrounding said protruding coreportion,

said booster shell cup containing an annular ring having a centralpassage and at its rearward end a central recess, said ferrule having aprotruding head portion at its forward end which seats in said recesswhen said booster end transfer arrangement is secured to said ferrule,

said annular ring having a conical inner surface tapering inwardly fromits forward end to said central 3 4 passage, said ring conical surfacesurrounding said References Cited uef com@ pomo?, UNITED STATES PATENTSwhereby no a1r gap 1s present between sald core and said filler toprevent propagation of high order Quin d to t'o of sad ll I YY a e nal nl er 5 3,326,127 6/1967 sehimmel 102-47 2. The device of claim 1including a retaining sleeve secured to said cord and holding saidbooster end trans- VERLIN R, PENDEGRASSD Primary Examiner ferarrangement to said ferrule.

